A while ago, I built Railator, for fun and to give me a chance to learn a few new things. It’s a very simple progressive web app that pulls train data from National Rail APIs and presents it. Much more recently, I added Pathfinder to it, which is a London-only tool to find paths (duh, really?) between any two given tram, DLR, tube, overground, or some rail stations. Again, this was mostly for fun and because it might help me learn a few more things, but I did have some ideas about how it could end up being real-world helpful for me. It turned out to be way more complicated than I was expecting.